TY - JOUR

T1 - Elasticity of (Mg0.87Fe0.13)2SiO4 wadsleyite to 12 GPa and 1073 K

AU - Liu, Wei

AU - Kung, Jennifer

AU - Li, Baosheng

AU - Nishiyama, Nori

AU - Wang, Yanbin

N1 - Funding Information:
This research was supported by National Science Foundation under Grant nos. EAR0635860 and EAR000135550 to B. Li. The in situ ultrasonic and X-ray experiments were carried out at GeoSoilEnviroCARS (Sector 13), Advanced Photon Source (APS), Argonne National Laboratory. GeoSoiEnviroCARS is supported by the National Science Foundation–Earth Sciences (EAR-0217473), Department of Energy–Geosciences (DE-FG02-94ER14466) and the State of Illinois. Use of the APS was supported by the U.S. Department of Energy, Basic Energy Sciences, Office of Energy Research, under contract no. W-31-109-Eng-38. Mineral Physics Institute publication no. 474.

PY - 2009/5

Y1 - 2009/5

N2 - Elasticity of (Mg0.87Fe0.13)2SiO4 wadsleyite has been measured at simultaneous high pressure and high temperature to 12 GPa and 1073 K using ultrasonic interferometry in conjunction with synchrotron X-radiation. The elastic moduli and their pressure and temperature derivatives are precisely determined using pressure-standard-free third-order and fourth-order finite strain equations. Combined with previous thermoelastic data on olivine, the density, velocity and acoustic impedance contrasts between α- and β-(Mg0.9Fe0.1)2SiO4 at 410-km depth are calculated along a 1673 K adiabatic geotherm. Both the third- and fourth-order finite strain equation fitting results give estimation of ∼33-58% olivine content in the upper mantle to account for a seismic discontinuity of ∼5% velocity jumps, and 8.5% (P wave) and 11.1% (S wave) impedance jumps at 410 km depth.

AB - Elasticity of (Mg0.87Fe0.13)2SiO4 wadsleyite has been measured at simultaneous high pressure and high temperature to 12 GPa and 1073 K using ultrasonic interferometry in conjunction with synchrotron X-radiation. The elastic moduli and their pressure and temperature derivatives are precisely determined using pressure-standard-free third-order and fourth-order finite strain equations. Combined with previous thermoelastic data on olivine, the density, velocity and acoustic impedance contrasts between α- and β-(Mg0.9Fe0.1)2SiO4 at 410-km depth are calculated along a 1673 K adiabatic geotherm. Both the third- and fourth-order finite strain equation fitting results give estimation of ∼33-58% olivine content in the upper mantle to account for a seismic discontinuity of ∼5% velocity jumps, and 8.5% (P wave) and 11.1% (S wave) impedance jumps at 410 km depth.

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U2 - 10.1016/j.pepi.2008.10.020

DO - 10.1016/j.pepi.2008.10.020

M3 - Article

AN - SCOPUS:67349282296

VL - 174

SP - 98

EP - 104

JO - Physics of the Earth and Planetary Interiors

JF - Physics of the Earth and Planetary Interiors

SN - 0031-9201

IS - 1-4

ER -